Adachi (written: 安達, 足立, 足達 or あだち in hiragana) is a Japanese surname.[1] Notable people with the surname include:
- Adachi (あだち), a member of the manga artist duo Adachitoka
- Akihiko Adachi (安達 明彦, born 1965), Japanese mixed martial artist
- Barbara Adachi, American businesswoman
- Chihaya Adachi (born 1963), Japanese physicist
- Adachi Ginkō (安達 吟光, 1853–1908), Japanese ukiyo-e artist
- Goro Adachi (安達 五郎, 1913–1999), Japanese ski jumper
- Hatazō Adachi (安達 二十三, 1884–1947), Japanese general
- Hirohide Adachi (足立 丈英, born 1999), Japanese footballer
- Jeff Adachi (1959–2019), American lawyer
- Adachi Kagemori (安達 景盛, died 1248), Japanese warrior, son of Morinaga
- Kaoru Adachi (安達 かおる, born 1956), Japanese film director, producer and editor
- Katsuji Adachi (安達 勝治, 1942–2010), better known as Mr. Hito, Japanese professional wrestler
- Kazuya Adachi (足立 和也, born 1990), Japanese slalom canoeist
- Ken Adachi (1929–1989), Canadian writer and literary critic
- Kenyi Adachi (born 1993), Mexican footballer
- Adachi Kenzō (安達 謙蔵, 1864–1948), Japanese politician
- Kiyoshi Adachi (安達 清, 1914–?), Japanese pole vaulter
- Mariko Adachi (足立 真梨子, born 1983), Japanese triathlete
- Masao Adachi (足立 正生, born 1939), Japanese screenwriter and film director
- Miho Adachi (足立 美穂, born 1979), Japanese sprint canoeist
- Mineichirō Adachi (安達 峰一郎, 1870–1934), Japanese judge
- Mitsuhiro Adachi (足立 光宏, born 1940), Japanese baseball player
- Mitsuru Adachi (あだち 充, born 1951), Japanese manga artist
- Adachi Morinaga (安達 盛長, 1135–1200), Japanese warrior
- Osamu Adachi (足立 理, born 1987), Japanese actor and singer
- Rika Adachi (足立 梨花, born 1992), Japanese television personality and actress
- Ryo Adachi (安達 亮, born 1969), Japanese footballer and manager
- Ryoichi Adachi (安達 了一, born 1988), Japanese baseball player
- Seiya Adachi (足立 聖弥, born 1995), Japanese water polo player
- Shinobu Adachi (安達 忍, born 1958), Japanese voice actress
- Shinya Adachi (足立 信也, born 1957), Japanese politician
- Shōtarō Adachi (足立 正太郎, 1901–1995), Japanese photographer
- Takumi Adachi (安達 巧, born 1966), Japanese sport wrestler
- Tomomi Adachi (足立 智美, born 1972), Japanese musician
- Toshiya Adachi (安達 俊也, born 1965), Japanese baseball player
- Tsubasa Adachi (足立 翼, born 2000), Japanese footballer
- Tsunamitsu Adachi (安立 綱光, 1901–1981), Japanese entomologist
- Tsutomu Adachi (あだち 勉, 1947–2004), Japanese manga artist and the older brother of Mitsuru Adachi
- Yasushi Adachi (足立 康史, born 1965), Japanese politician
- Yuji Adachi (足立 祐二, born 1964), Japanese musician and songwriter
- Yumi Adachi (安達 祐実, born 1981), Japanese actress and singer
- Yumi Adachi (synchronised swimmer) (足立 夢実, born 1989), Japanese synchronized swimmer
- Yurie Adachi (足立 友里恵, born 1985), Japanese ice hockey player
- Yusuke Adachi (足達 勇輔, born 1961), Japanese footballer and manager
- Yuto Adachi (安達 祐人, born 1998), Japanese rapper of K-Pop group Pentagon
- Yositaka Adachi (born 1962), Palauan politician